This invention relates to exterior rearview mirrors for vehicles and, more particularly, to a vehicular rearview mirror system allowing repositioning of the mirror reflector for desired time periods to view areas adjacent the vehicle which otherwise would be hidden from view in the driver""s blind spot to improve safety during lane changes, merging with or passing of other vehicles.
Continuing efforts to improving occupant safety in the automotive and vehicular industry has recently focussed attention on the unsafe condition when driving a vehicle known as the xe2x80x9cblind spot.xe2x80x9d In the typical rearview mirror system incorporated in most vehicles today, an interior rearview mirror assembly is mounted on the inside of the vehicle and includes a mirror reflector used by the driver to view rearwardly of the vehicle to judge traffic to allow passing, lane changes, operation in reverse and the like. In conjunction with the interior rearview mirror assembly, a passenger side and/or driver side exterior mirror assemblies are normally used by the driver to extend the field of view both laterally and rearwardly of the vehicle. However, when using both the interior and exterior mirror reflectors of such assemblies, a driver normally encounters an area next to the vehicle that cannot be viewed with either the interior or exterior mirror reflector. When passing another vehicle, changing lanes on a highway or merging into freeway traffic, such a blind spot experienced by the driver using existing mirror systems can often hide an adjacent vehicle leading to potentially injurious conditions or accidents.
To improve a driver""s vision and help reduce blind spots while driving, a blind spot actuator can be added to an exterior rearview mirror assembly which will quickly reposition the reflective surface of the mirror when activated such that the blind spot size decreases greatly or is eliminated. When deactivated, the blind spot actuator quickly returns the reflective mirror surface to its original position for normal rearward viewing.
A variety of blind spot actuators have been previously proposed. One prior known assembly includes a hinge plate, spring and electric motor combination incorporated in the exterior rearview mirror. When in the normal driving position, the electric motor is deactivated and the spring is retracted. However, when activated, the electrical motor drives a gear mechanism to change the angular position of the mirror. Electric power is continuously supplied to the motor in order to hold the mirror in the extended position. When power is removed, the force applied by the motor is removed and the spring applies a return force to the mirror which urges the mirror back to its normal position. Such an assembly, however, requires the motor to be in a stall position with electrical power applied as long as the driver desires to view the blind spot. Since the blind spot actuator will be used very frequently by a vehicle driver, the large cycle requirement for the assembly in which the stall position is maintained in each cycle reduces the life of the electric motor.
In addition to severe requirements for the drive motor, the above system may experience significant vibration distortion for the driver when viewing the system while driving on a highway. For example, the spring which is extended when the blind spot actuator is activated is in a relaxed position when the reflective surface is in the normal position. This allows road shocks and other vibration to affect the mirror. In addition, the drive motor assembly is attached to the mirror holder. Such additional weight of the drive motor may degrade the vibration performance of the reflective surface.
Further, many prior known electrically operated blind spot actuator systems such as that shown in U.S. Pat. No. 4,834,522 to Janowicz U.S. Pat. Nos. 4,971,430; 5,097,362; and 5,159,497 to Lynas; U.S. Pat. No. 5,033,835 to Platzer, Jr.; and U.S. Pat. No. 5,745,310 to Mathieu have rotated the reflective surface of the mirror about a pivot axis centered within a surrounding mirror housing. Because of such positioning, the remote ends of the reflective mirror surface must travel a significant distance within the housing to accommodate all necessary adjustment positions. Such movement requires additional space within the mirror housing and reduces the amount of available housing area useful for positioning other required mirror assembly components. In addition, the pivot supports for the reflective mirror element in such prior known systems including the above Janowicz, Lynas and Mathieu patents have been of significant size and cause the reflective mirror surface to be positioned a large distance from the center of the adjustment mechanism. This likewise decreases vibration performance of the overall assembly and creates manufacturing difficulties in forming an interchangeable system in which a single mirror housing can include either a blind spot actuator or a normal mirror glass as desired.
Therefore, prior known blind spot actuating systems for rearview mirror assemblies have suffered from a lack of reliability and short cycle life, decreased vibration performance, a lack of efficient use of space within the mirror housing, and reduced ability to provide system interchangeability.
Accordingly, the present invention provides a vehicular exterior rearview mirror assembly blind spot viewing system which overcomes problems encountered with the prior known systems and provides a versatile, lower cost, reliable blind spot actuator having improved vibration performance for use on vehicles such as automobiles and trucks.
In one form, the invention is an exterior rearview mirror assembly blind spot viewing system for vehicles comprising an exterior rearview mirror assembly including a reflective mirror element, and a pivot member for pivotally mounting the reflective mirror element on the assembly to adjust the position of the mirror element for different fields of view for different vehicle drivers. The pivot member pivotally mounts the mirror element on an axis generally aligned with the center of the mirror element. A support member includes a joint for movably mounting the reflective mirror element between a first rearward viewing position and a blind spot viewing position. The joint is spaced laterally outwardly of the center axis. A motive power source is provided for moving the support member and the reflective mirror element on the joint between the first rearward viewing position and the blind spot viewing position. The motive power source includes an electric motor, a gear and a threaded member driven for extension and retraction by the electric motor and gear. The blind spot viewing position provides an enhanced field of view for the vehicle driver in the area adjacent the vehicle on which the assembly is mounted.
In another form of the invention, the pivot member pivotally mounts the mirror element on an axis at a predetermined position with respect to the mirror element. The joint of the support member is spaced laterally on one side of the axis at a first position, while the motive power source including an electric motor, gear and threaded member is mounted on the pivot member at a position spaced laterally on another side of the axis generally opposite to the first position.
In a further form of the invention, the motive power source including an electric motor, gear and threaded member is mounted on the pivot member at a position spaced from the axis, while the threaded member is pivotally secured to the pivot member.
Preferably, the threaded member may include a threaded post pivotally joined to the support member. Alternately, the electric motor includes a crank member pivotally secured between the motor, gear and support member. In yet another form, the threaded member, which is extended and retracted by the motor and gear, may include a push/pull cable connected to the support member.
In a preferred form of the invention, the pivot member includes an actuator for adjusting the mirror element position, the actuator preferably being an electric actuator remotely controlled from the interior of the vehicle on which the assembly is mounted. The support member is movably mounted on the pivot member such that the joint therebetween positioned adjacent the peripheral edge of the mirror element. More preferably, the support member may include a backing member secured to the mirror element while the assembly includes a housing. The actuator is fixedly mounted to the housing and the pivot member includes a pivot plate pivotally secured to the actuator on the center axis. The joint extends between the pivot plate and the backing member.
In another form of the invention, the assembly includes a housing and a mounting plate within the housing. The pivot member includes an actuator, such as an electric actuator, for adjusting the mirror element position, the actuator being fixedly mounted on the support member. The joint extends between the support member and the mounting plate such that when the mirror assembly is moved to the blind spot viewing position, the support member, pivot member including the actuator and the reflective mirror element are all moved in unison.
In various other forms of the invention, the motive power source may include a muscle wire or an electric solenoid and one of various forms of connection to the support member.
In other preferred aspects of the invention, an electrical control for the motive power source is provided for ease of use by all vehicle drivers. In one form, a switch may be activated by the driver to move the reflective mirror element to the blind spot viewing position and to return to the normal rearward viewing position upon release of the switch. A current limiting device is preferably incorporated to limit the current applied to the electric motor or to shut off the electric current when the motor is in the blind spot viewing position. Alternately, other switch devices could be used such as a push-push switch in which the driver pushes a button or other activating member to move the reflective mirror element to the blind spot viewing position and pushes the same activating member to return the mirror element to its normal rearward viewing position when desired. Alternately, an on/off type switch can be used to move the reflective mirror element to its blind spot viewing position after which the switch is moved to the alternate position to return the mirror element to its normal rearward viewing position.
The present invention overcomes numerous problems encountered with prior blind spot viewing systems in exterior vehicular rearview mirrors by providing a reliable, long lasting easily manufactured assembly which allows momentary actuation to view the blind spot area when changing lanes, merging, or passing another vehicle without requiring significantly increased space within the rearview mirror housing. One of several types of electric drive motors can be incorporated which do not require continued application of electric power while in the blind spot viewing position and, therefore, have significantly increased life span and cycle capacity. In addition, the structure of the present invention improves vibration performance over other known systems and reduces unwanted blurring in the reflective mirror element when viewed by the vehicle driver. In addition, the blind spot viewing system of the present invention may be incorporated in an exterior rearview mirror on either the driver or passenger side of the vehicle to enable viewing of blind spots on either side of the vehicle.
These and other objects, advantages, purposes and features of the invention will become more apparent from a study of the following description taken in conjunction with the drawings.